Sulfur containing fluoroalkyl amines are useful as intermediates for compounds which are in turn useful for imparting water and oil repellency to textiles. Sulfur containing fluoroalkyl amines used in this manner may be found in Example 8 of Rondestvedt et al. (U.S. Pat. No. 3,655,732) wherein they are made by reacting an iodo-fluoroalkyl with an aminoalkyl thiol. Specifically, Rondestvedt et al. teaches reacting CF3(CF2)5(CH2)2I (an iodo-fluoroalkyl) with HS—CH2CH2—NH2 (an aminoalkyl thiol) to make CF3(CF2)5(CH2)2—S—CH2CH2—NH2 (a sulfur containing fluoroalkyl amine).
One disadvantage of preparing sulfur containing fluoroalkyl amines according to the method disclosed by Rondestvedt et al. is that crude product obtained by such a method can contain up to 29 mole percent of impurities. To increase yield and reduce the amount of these impurities, tert-butanol has been used as reaction solvent (J. Org. Chem. 1977, 42, 2680-2683); however, tert-butanol is relatively expensive and subsequent isolation of the product can be unpredictably tedious due to foam and emulsion formation.
In addition to problems of poor yield, another disadvantage of preparing sulfur containing fluoroalkyl amines according to the method disclosed by Rondestvedt et al. is that such a method is incapable of producing oxidized forms of sulfur containing fluoroalkyl amines. While Rondestvedt et al. disclose a method of making sulfur containing fluoroalkyl amines such as CF3(CF2)5(CH2)2—S—CH2CH2—NH2, the method of Rondestvedt et al. cannot produce corresponding oxidized forms such as CF3(CF2)5(CH2)2—S(O)—CH2CH2—NH2 or CF3(CF2)5(CH2)2—S(O)2—CH2CH2—NH2.